... the immobilized conventional antibody poses less prominent spatial constraints than the immobilized superagonistic antibody. ... However, when these antibodies are immobilized (either by secondary antibody bound to plastic or by Fc receptors on other cells ... Immobilized superagonistic antibodies bound to CD28 exclude CD45 phosphatases completely and the signal leading to T-cell ... Binding of both conventional and superagonistic (mitogenic) antibodies in suspension does not constrict the dephosphorylation ...